2019年9月1日 定制format

Posted 2022-09-18 python1988

x=‘000‘.format(‘a‘)
print(x)

class Date:
    def __init__(self,year,mon,day):
        self.year=year
        self.mon=mon
        self.day=day


d1=Date(2099,1,2)
y=‘0.year0.mon0.day‘.format(d1)
z=‘0.year-0.mon-0.day‘.format(d1)
print(y)
print(z)

>>>>

aaa
209912
2099-1-2

 

format_dic=
    ‘ymd‘:"0.year:0.mon:0.day",
    ‘m-d-y‘:‘0.mon-0.day-0.year‘,


class Date:
    def __init__(self,year,mon,day):
        self.year=year
        self.mon=mon
        self.day=day
    def __format__(self, format_spec):
        print(‘format 执行‘)
        if not format_spec or format_spec not in format_spec: #如果 format_spec为空，或者不在字典的格式内
            format_spec=‘ymd‘
        fm=format_dic[format_spec]#通过字典来进行选择
        return fm.format(self)


d1=Date(2099,1,2)
zz=format(d1,‘ymd‘)
ww=format(d1,‘m-d-y‘)
print(zz)
print(ww)

》》》》

format 执行
format 执行
2099:1:2
1-2-2099